Good review. It's nice to see balanced reviews, not every bat can be the best bat you've ever owned.
Sure, H4L are very good at what the do, but they can't get it right 100% of the time. I hope they read this review and try to work on what may have gone wrong with this one, even though as you say, it's second hand and probably atleast 12 months old.
As for the bat itself, I'm surprised the pick up is heavy, there looks to be a fair bit of concaving so I would have expected it to pick up light. Is this a case of the new fashion that's about to sweep bats... High-Density willow?